The present invention relates to an expandable bone implant and, more particularly to an oral implant having radially extendable anchoring means.
Implant dentistry involves the restoration of one or more teeth in a patient's mouth using artificial components. Such artificial components typically include a dental implant and a prosthetic tooth and/or a final abutment that is secured to the dental implant. Generally, the process for restoring a tooth is carried out in three stages.
Stage I involves implanting the dental implant into the alveolar bone (i.e., jawbone or cortica) of a patient. The surgeon first accesses the alveolar bone through the patient's gum tissue and removes any remains of the tooth to be replaced. Next, the specific site in the alveolar bone where the implant will be anchored is prepared by drilling and/or reaming to accommodate the width/diameter of the dental implant to be inserted. Then, the dental implant is inserted into the hole, typically by screwing, although other techniques are known for introducing the implant in the jawbone.
After the implant is initially installed in the bone, a temporary healing cap/screw may be secured over the exposed proximal end in order to seal the internal bore of the implant. The patient's gums are then sutured over the implant to allow the implant site to heal and to allow desired osseointegration to occur. Complete osseointegration typically takes anywhere from three to ten months.
During stage II, the surgeon reaccesses the implant fixture by making an incision through the patient's gum tissues. The healing cap/screw is then removed, exposing the proximal end of the implant. Typically, an impression coping may be attached to the implant and a mold or impression is then taken of the patient's mouth to accurately record the exact position and orientation of the implant within the mouth. Stage II is typically completed by attaching to the implant a temporary healing abutment or other transmucosal component to control the healing and growth of the patient's gum tissue around the implant site. In a modified procedure, an abutment or other transmucosal component is either integrally formed with the implant or is attached to the implant during stage I. In such a procedure, stages I and II are effectively combined in to a single stage.
Stage III involves the fabrication and placement of cosmetic tooth prosthesis to the implant fixture. The plaster analogue provides laboratory technicians with a model of the patient's mouth, including the orientation of the implant fixture and/or abutment relative to the surrounding teeth. Based on this model, the technician constructs a final restoration. The final step in the restorative process is replacing the temporary healing abutment with the final abutment and attaching a final prosthesis to the final abutment.
The dental implant is typically fabricated from pure titanium or a titanium alloy and includes a body portion and a collar. The body portion is configured to extend into and osseointegrate with the alveolar bone. The top surface of the collar typically lies over, under, or flush with the crest of the jawbone bone. The final abutment typically lies on the top surface and extends through the soft tissue, which lies above the alveolar bone. As mentioned above, the abutment supports the final prostheses. Typically, the coronal or crown portion of the collar and the portions of the final abutment that extend through the soft tissue have machined- or polished surfaces. This is believed in the art to prevent the accumulation of plaque and calculus and facilitates cleaning.
Conventional dental implants that provide the foundation for a prosthetic tooth as described hereinabove require a substantially solid, dense bone in which to be inserted and/or installed and/or inlaid. If there is insufficient bone quantity, quality or density, for example soft and/or osteoporotic bone, conventional implants may suffer osseointegration failure, loosen and fail.
An expandable dental implant may comprise a screw which is torqued into a jacket having multiple deformable ends that expand into the surrounding bone; as exemplified by U.S. Pat. No. 6,332,778 (Choung), the contents of which is incorporated herein by reference in their entirety. The larger diameter provided by the expanded multiple ends, may aid in locking the implant in the osteoporotic bone.